1. Field of the Invention
The present invention relates to a cross-contamination prevention system used in an automatic analyzer for qualitatively or quantitatively analyzing samples of a living body, such as serum and urine. More particularly, the present invention relates to a cross-contamination prevention system capable of greatly cutting down a preparation time required for setup of the analyzer, such as installation of the analyzer and introduction of a new reagent, and also relates to an automatic analyzer equipped with the cross-contamination prevention system.
2. Description of the Related Art
In an automatic clinical analyzer, it is general to employ a probe or the like in common for aspirating a sample, a reagent, etc. and dispensing them into another container, and to wash the probe or the like for reuse after aspirating one kind of sample, reagent, etc. In those pipetting steps, components of one sample, components of one reagent, and components of one reaction product, which have not been completely washed out, may mix with components of another sample, components of another reagent, and components of another reaction product, thereby giving rise to a reaction not intended and imposing an adverse influence upon a measured value of an item to be analyzed. Such an influence is called cross-contamination. A data failure caused by the cross-contamination has been prevented in the past as follows. An operator of the automatic analyzer inquiries a reagent manufacturer and an analyzer manufacturer of not only information regarding combinations (pairs) of reagents which may affect measured values by the cross-contamination, but also information regarding methods to prevent the influence. The operator actually carries out a cross-contamination test for a period of about 2 to 4 days, and validates the pairs causing the cross-contamination based on the test. The operation for preventing the cross-contamination is then carried out in consideration of the test result. In the prevention operation, information to prepare a program is entered on an operating screen to change the sequence of analyzing steps so that the pair of reagents causing the cross-contamination will not be analyzed in succession, or to insert a washing step with a detergent between steps of analyzing those reagents if the sequence of analyzing steps cannot be changed.
On the other hand, assuming a simultaneous measurement of, e.g., 10 items to be carried out in the validation test for the cross-contamination, there are a number 10×9=90 of item combinations that may possibly cause the cross-contamination. In the case of carrying out the validation test for 90 combinations, if a two-stage test made up of, for example, (1) a screening test and (2) a validation test is performed as usual, a test period of several days is required. Further, when new analysis items are added later after the start of routine analysis, an addition of the items increases the number of combinations to be tested in accordance with the equation of (the number of added items (1)×the number of all existing items (10)×2=20) for an addition of one item because the test is made on the added item with respect to each of all the existing items. Thus, the quantity of work required for the validation test is very large. The more the number of added items, the larger is the quantity of the required work. Further, information regarding the cross-contamination between reagents produced by different reagent manufacturers is sometimes not checked by the reagent manufacturers and therefore not sufficient. In such not a few cases, the operator must carry out the validation test for those reagents by himself or herself.
JP,A 5-240867 and JP,A 7-270428 propose it to cope with the above-mentioned problems by reducing time and labor required for item selection work, etc. in connection with the cross-contamination test. Also, JP,A 10-010131 proposes a method for enabling the operator to find an opponent item of the cross-contamination with high efficiency after a data failure has occurred by the cross-contamination.